An analytic method of quarter-wavelength shifted DFB guiding structures

Optical filtering characteristics of planar distributed feedback (DFB) guiding structures which have /spl Lambda//4 phase-shift region are evaluated by using the equivalent network based on a newly developed concept of Floquet's theorem and the bisection principle (Babinet's theorem). The numerical results reveal that this method offers a simple and convenient algorithm to analyze the filtering and oscillating characteristics of /spl Lambda//4 phase-shifted DFB configurations as well as decreasing dramatically the computational time.